Remove |using base::StringPiece| from net/spdy header files.

net/spdy/hpack/hpack_static_table.cc

Index: net/spdy/hpack/hpack_static_table.cc
diff --git a/net/spdy/hpack/hpack_static_table.cc b/net/spdy/hpack/hpack_static_table.cc
index 8ee1d0bdd9c79fe8dff672beb06769d6b9a64d7e..b954c3482d734511907aa3a4da0d3c68f863d23e 100644
--- a/net/spdy/hpack/hpack_static_table.cc
+++ b/net/spdy/hpack/hpack_static_table.cc
@@ -21,10 +21,11 @@ void HpackStaticTable::Initialize(const HpackStaticEntry* static_entry_table,
   int total_insertions = 0;
   for (const HpackStaticEntry* it = static_entry_table;
        it != static_entry_table + static_entry_count; ++it) {
-    static_entries_.push_back(HpackEntry(StringPiece(it->name, it->name_len),
-                                         StringPiece(it->value, it->value_len),
-                                         true,  // is_static
-                                         total_insertions));
+    static_entries_.push_back(
+        HpackEntry(base::StringPiece(it->name, it->name_len),
+                   base::StringPiece(it->value, it->value_len),
+                   true,  // is_static
+                   total_insertions));
     CHECK(static_index_.insert(&static_entries_.back()).second);
 
     ++total_insertions;